Relational Algebra Query

[muniba]

Relational algebric expression for the following:
Draw two relational algebra query trees for the following query and show that one query tree is more eficient than the other.
"Give the number of treatments given by "Dr.Albert" for all the appointments made during the period January to June 2007"

thanks

[epots9]

Please read the posting guidelines in regarding to Posting Homework Questions.

Moved to the Misc Forums.

**Moved from Programming Challenges